Dynamics modelling and simulation of super truss element based on non-linear beam element

A mobile crane equipped with a lattice boom system is widely used to lift the heavy load on construction sites. Even though the lattice structure can provide strong support with limited mass, the inertia force of the lattice boom is still not neglectable, so is the heavy lifting load. Therefore, the dynamic response of the lattice boom is important but also time-consuming due to a large number of degrees of freedom. In engineering, the truss beam is often simplified as a continuous beam, but because of the noncontinuity of the truss, this direct modelling method cannot truly reflect the actual dynamics of the truss. In this paper, a detailed Super Truss Element formulation for nonlinear truss elements is proposed to reduce the number of degrees of freedom. The formulation uses nonlinear spatial Timoshenko Beam based on co-rotational coordinate and dynamic condensation approach with three assumptions. After parameterizing the characteristics of the Super Truss Element, a nonlinear method for the calculation of the mass matrix and force vector in a large displacement and rotation is developed. A dynamic simulation of the spatial motion of the lattice boom crane is performed and the results are analysed.